Why were there no large animals in Pre-Columbian Americas for transportation and war, beasts of burden and livestock like there were in the Old World?

by TinyBaron

I can never find an explanation. I hear about the ice ages and human hunting but those also happened in the Old World.

axeteam

Large animals? How large? The incans used llamas to traverse the Andes mountains but I’m not sure if they count as “large”.